Dissolving cellulose



- UNITED STATES PATENT OFFICE. Q

ISIDOR KITSEE, F PHILADELPHIA,PENNSYLVANIA.

DISSOLVING CELLULOSE.

No Drawing. Application filed October 18, 1919, Serial No. 331,581.

Specification of Letters Patent. I Patented Sept. 20, 1921.

Renewed August 4, 1921. Serial for the dissolving action, but I will describe here my invention as applied to the production of what is commercially known as a cuproammonium cellulose, that is a solid cellulose dissolved by the action of copperammonia.

To day, to produce the formation of a dissolved cellulose with the aid of copper-am- -moni a, the method most generally employed is, to immerse the fiber, such as cotton, in a cuproammonium solution, made either by dissolving metallic copper in ammonia or by adding an oxid, such as a sub-oxid of copper to ammonium hydroxid.

This process requires days and often weeks to produce the required result to dissolve the cotton and produce a formation of a solution containing the cellulose in dissolved state.

Careful experiments have revealed the fact, that the process of dissolving the fiber can greatly be accelerated through the fr1ctional or rubbing action of the fiber on the metallic copper, sufiicient ammonium hydroxid being supplied. I will state, that if a wad of cotton is briskly rubbed on a plate of copper even if the same has a smooth surface, the wad of cotton previously saturated with aqueous ammonia, it only requires a few seconds till the first layer of the fiber is dissolved. Basing now my invention on this discovery, I will here describe a few of the means with the aid of which this my invention may be employed to produce the required dissolved cellulose commercially.

A very simple way of practising this my invention is :-to place the saturated cotton between two plates of copper, one revolving from right to left and the second revolving, by preference from left to right. Means such as electric motors may make the revolving automatic. It is suggested to inclose this device in a tight inclosure so as to prevent undue evaporation of the ammonia.

The under plate may be replaced by a receptacle into which the fiber and ammonia is deposited.

To increase the frictional action small pieces of copper may be intermixed with the fiber before the same is deposited in the receptacle. Instead of revolving disks, frictional rolls may be substituted, or a disk and roll may jointly form the frictional or rubblng action. If required revolving paddles may be added so as to increase the necessary friction. It is obvious, that if the process should be a continuous one, ingress for the fiber and liquor and outlet for the dissolved cellulose has to be provided.

Instead of saturating the fiber with aque-' ous ammonia, the fiber may be saturated with plain water and gaseous ammonia carr1ed into the device, so as to be taken up by the water with which the cotton is saturated,

as the great afiinity of gaseous ammonia for moisture is well understood and the process results satisfactorily.

Wherever I use the expression rubbing or friction, I include all processes whereby a frictional action may be accomplished.

Tests were made with cotton rags and paper, such as old newspapers and it was found that the cuproammonium cellulose was just as easily produced with the process above described, as with the pure cotton. It

is obvious, if the resultant product is to be of a light color, the rag or paper has to be bleached, so as not to give a dark colored solution;

I have so far described the production of cuproammonium cellulose. To persons versed in the art it is well known that this cuproammonium cellulose is to day used in the manufacture of artificial silk. Generally speaking, the cuproammonium cellulose is forced through very fine apertures into a solution adapted to dissolve out the copper salt and produce thereby a thread, solid and pliable enough to 'be later on wound upon a drum, colored and then woven into required textile. In some cases the solution itselfis colored. I

Some manufactures use an acid as the precipitating medium, some manufactures use a double alkali salt and in some instances even a metallic carbonate is used for this bath.

Havin now described my what I ciaim as new and desire to secure Letters Patent is 1. The process of dissolving cellulose which consists in subjecting the cellulose to be dissolved to a rubbing action in conjunction with copper in the presence of ammonia.

2. The process which consists in producing friction between the fiber to be dissolved and copper in the presence of a solvent agent, thereby dissolving said fiber.

3. The method which consists in dissolving a cellulose through continuous friction with copper, the fiber -moistened with a. liquid, adapted to act as a solvent.

4. The method of dissolving cotton or like fiber which consists in producing a rubbing action between said fiber and copper in the presence of a liquid adapted to act as a solvent.

5. The method of dissolving cotton or like fiber which consists in producing a rubbing action between said fiber and a metal adapted to dissolve said fiber in the presence of ammonia. I

6. The production of cuproammonium cellulose through the rubbing action of a suitable fiber on metallic copper in the presence of ammonia.

7. In the production of a cuproammonium cellulose the improvement which consists in intermixing copper particles with a. fiber to be dissolved, and producing a rubbing invention,-

action between the metal and the fiber in the presence of ammonia.

8. The process of dissolving cellulose dissolved and adjacent fibers are exposed "and subjected to said rubbing action.

10. In the art of dissolving'cellulose the improvement which consists in moistening the cellulose to be dissolved with water, producing between said cellulose and a suitable metal rubbing or frictional action and subjecting during said action the cellulose to a suitable gaseous agent.

11. The method of producing cuproammonium cellulose, useful for artificial silk which consists in subjecting paper to the rubbing or frictional'action of metallic copper in the presence of ammonia.

12. The method of dissolving a fiber which consists in subjecting said fiber to frictional action in the presence of a solid and liquid agent, both agents combined acting as the solvent.

In testimony whereof I aflix my signature.

ISIDOR KITSEE. Witnesses:

Durr C. LAW, E. E. MILLER. 

